Cooler



Sept. 2, 1941. POWERS 2,254,807

COOLER Filed Sept. 7, 1940 2 Sheets-Sheet l 49'" I :3: iii 7 \II 1 iii INVENTOR 55;. Fran/r ZPowers L'II'IIII. I A

Sept. 2, 1941. F. T. POWERS COOLER Filed Sept. 7, '1940 2 Sheets-Sheet 2 l I i INVENTOR flan/r TPOn ers Patented Sept. 2, 1941 UNHTED STATES PATENT OFFICE COOLER Frank T. Powers, Glen Cove, N. Y.

Application September 7, 1940, Serial No. 355,861

Claims.

The invention relates to an apparatus for use in the making of photo-mechanical printing plates and more particularly to an apparatus for cooling plates which have been heated in the process of making.

The objects and advantages of the invention will be set forth in part hereinafter, and in part will be obvious therefrom, or they may be learned by one having a knowledge of the art to which it pertains through practice with the invention.

The invention consists in the novel parts, constructions, arrangements, combinations and improvements shown and described herein.

In the accompanying drawings, which are referred to herein and which constitute a part hereof, is shown a preferred embodiment of the invention which is intended to be illustrative of, but not restrictive of, the scope of the invention, as other arrangements and modifications may be used in carrying out the invention without de parting from the spirit or scope thereof, within the limits of the appended claims.

Of the drawings:

Fig. 1 is a side view, partly in section, of the apparatus.

Fig. 2 is a detail of a clip for holding the membrane to its frame.

Fig. 3 is a plain view of the top of the apparatus.

Fig. 4 is a detail of an alternate construction of the top of the tray and the membrane attachment.

In the process of etching photo-mechanical printing plates, as for example half tone plates or line cuts, it is necessary to heat the plates a number of times, either to burn-in an enamel coating or to melt a fusible resist such as dragons blood, or for other reasons. Each time a plate is heated it must be cooled to a temperature at which it can be handled by the operator without physical discomfort. It is important that during this cooling process no water, or other cooling fluid, or any foreign matter of any sort shall reach the printing surface of the plate. Heretofore, it has been common practice to accomplish this cooling by applying water to the back of the plate as is described, for example, in Patents Nos. 1,373,909 and 1,574,849,

While the application of water to the back of the plate only is not harmful if it is applied simultaneously and uniformly over the entire back surface of the plate, there is, nevertheless, an ever-present hazard that a drop of water may accidentally or unavoidably reach the printing surface of the plate, or that the operators hands may become wet, by reason of his handling a plate which is wet on the back, and so inadvertently moisten the printing side of the plate.

It was partially to overcome this disadvantage and to eliminate this hazard that my invention was aimed, which is shown and described in my co-pending application Serial Number 355,860.

The present invention is an improvement on the above identified invention in that the construction is greatly simplified, and the cost of construction materially reduced, without loss of efliciency and without losing any of the advantages thereof.

Referring more particularly to the embodiment of the invention shown by way of example in the drawings, a tray or reservoir l is shown supported by four legs 2 which may advantageously be braced by angle irons 3 for greater rigidity. Within the tray, at its center, is a propeller blade 4 having a vertical shaft 5 which passes through a stufling box 6 in the bottom of the tray and has attached to its lower end a driving pulley I belted to the pulley 8 of a motor 9 bracketed between two of the legs of the machine. The motor 9 is shown mounted on a base l0 hinged at II and provided with an adjusting screw l2 and a spring l3 to permit easy adjustment of the tension of the driving belt and to take up for the stretch of the belt in service. Within the tray are four vertical stationary vanes or deflecting plates I4 the function of which is to prevent undue swirl of th liquid in the tray when the propeller 4 is rotating.

At the top of the tray, and floating on the surface of the liquid within the tray the normal level of which is indicated at A is a thin, flexible, fluid-impervious membrane [5 covering substantially the entire area of the tray, and with its edges attached to a light rectangular frame It over the outside of which the edges of the membrane are folded as shown in detail in Figure 2 and held in place by clips l1. As a means of supplying or replenishing the cooling fluid and to keep it at a constant level within the tray, as indicated at A, a supply pipe [8 and a valve l9 are provided. For draining the tray a drain pipe 20 and a valve 2| are also provided.

An alternate method of supporting the membrane I5 is shown in Fig. 4 in which the edges of the membrane are clamped to the top edge of the tray I by means of an angle frame 22.

The angles 23 shown in Fig. I serve to stiffen and make more rigid the bottom of the tray I and to better support the propeller assembly. The angles 24 serve as a rest or support for the frame l5 of the membranous top, in case the liquid level, indicated at A, becomes low.

The manner of operation of the invention is as follows: The tray I having been filled to the level indicated at A with cooling fluid, preferably water, the motor 9 is started which rotates the blades of the propeller 4 in the direction indicated by the arrow in Fig. 3. The action of the propeller is to force a rapid upward fiow of the liquid up against the underside of the membrane l5 in such volume that there is a resultant rapid circulation of liquid Within the tray under the membrane in the direction indicated by the arrows. The plate B, to be cooled, is laid upon the top surface of the membrane l5, at its midportion.

This rapid circulation of liquid, directed particularly against the mid-portion of the under surface of the membrane, cools the membrane so rapidly and effectively that as the heat of the plate is absorbed by the thin membrane on one side it is immediately conducted through the membrane and picked up and carried away by the cooling fluid by reason of the very rapid circulation of cooling fluid beneath the membrane.

In the interval of twelve to fourteen seconds a hot plate whose usual average temperature is about 250 to 300 F. is cooled to a temperature permitting its handling without physical discomfort by the operator, or about 125 to 150 F.

- I find that the use of a high velocity of circulation of the cooling liquid when directed against the membrane immediately under the plate being cooled, even though the cooling liquid be at room temperature is substantially as effective as a cooling means as the much cooler liquid described in myco-pending application named above with its lower rate of circulation. Thus the substitution of high velocity of circulation for the lower temperature of cooling liquid without sacrifice of the desirable qualities enumerated has resulted in a substantial saving in cost and in simplicity of construction and in maintenance, labor and cost. I have found for example, that starting with the liquid at 70 F. and cooling one plate after another for several hours, the temperature of the liquid gradually increased until it became luke warm or about 105 to 110 F. and there remained. The cooling time for the plates was about 12 seconds at the beginning and gradually increased to about 15 seconds at the end.

Having described my invention so that one skilled in the art to which it pertains can make and use the same I now state what I believe to be new and novel and for which I pray that Letters Patent be granted.

I claim:

1. An apparatus for cooling photo-mechanical printing plates comprising in combination a re ceptacle for a cooling liquid, a cooling liquid therein, a thin, flexible, liquid-impervious membrane in contact with the surface of the cooling liquid and adapted to receive and support, in intimate contact therewith, the plate to be cooled, a propeller within said receptacle, submerged in said liquid, and adapted to direct a rapid flow of said liquid against the mid-portion of the said membrane, and means for rotating said propeller.

2. An apparatus for cooling photo-mechanical printing plates comprising in combination a receptacle for a cooling liquid, a cooling liquid therein, a liquid-impervious membrane in contact with surface of the cooling liquid and adapted to receive and support, in intimate contact therewith, the plate to be cooled, means within said receptacle, submerged in said liquid, adapted to cause a ilow of said liquid against the under side of said membrane.

3. An apparatus for cooling photo-mechanical printing plates comprising in combination a receptacle for a cooling liquid, a cooling liquid therein, a membrane in contact with surface of the cooling liquid and adapted to receive and support in intimate contact therewith, the plate to be cooled, means adapted to cause a rapid flow of said liquid against the mid-portion of the under side of said membrane.

4. An apparatus for cooling photo-mechanical printing plates comprising in combination, a receptacle for a cooling liquid, a cooling liquid therein, a liquid-impervious membrane in contact with surface of the cooling liquid and adapted to receive and support in intimate contact thereith, the plate to be cooled, means including a propeller within said receptacle submerged in said liquid adapted to cause a flow of said liquid against the under side of said membrane.

5. An apparatus for cooling photo-mechanical printing plates comprising in combination a receptacle for a cooling liquid, a cooling liquid therein, a liquid-impervious membrane in contact with surface of the cooling liquid and adapted to receive and support in intimate contact therewith, the plate to be cooled, means including a propeller within said receptacle submerged in said liquid adapted to cause a flow of said liquid against the under side of said membrane and means for rotating said propeller.

FRANK T. POWERS. 

